Filter



FIG. 1 is a perspective view of a filter according to our new design;

FIG. 2 is front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines in the drawing depict portions of the filter that form no part of the claimed design. 

CLAIM The ornamental design for a filter, as shown and described. 